The Star Tribune won journalism’s highest honor Monday, not once, but twice, taking Pulitzer Prizes for local reporting and for editorial cartooning.

Brad Schrade, Jeremy Olson and Glenn Howatt won the reporting honor for their “powerful series of reports on the spike in infant deaths at poorly regulated day-care homes, resulting in legislative action to strengthen rules,” judges said in announcing the award. Since the series ran, the number of deaths at day cares has dropped dramatically.

“I’m kind of speechless,” a smiling Schrade said minutes after dozens of newsroom colleagues delivered a ­sustained standing ovation.

Steve Sack won the editorial cartooning award, for commentary on news ranging from Michele Bachmann’s presidential run to Lance Armstrong’s blood-doping coverup. Judges noted Sack’s “diverse collection of cartoons, using an original style and clever ideas to drive home his unmistakable point of view.” He’s been the Star Tribune’s editorial cartoonist since 1981 and was a finalist for the ­Pulitzer in 2004.

Sack, who has drawn more than 7,800 cartoons for the paper in 32 years, said he had no idea he’d won until his editor, Scott Gillespie, stopped at his desk to break the news.

“I didn’t believe him, I thought he was messing with me,” Sack said softly as he clutched a bottle of champagne and greeted well-wishers.

Video (03:48): Cartoonist Steve Sack wins Pulitzer

‘Always been so proud’

“I’ve always been so proud of working for this newspaper,” he added. “For something like this to happen, I feel like it’s for all of us.”

Both awards carry a $10,000 prize.

“It matters to me that this was for journalism that makes a difference,” said Nancy Barnes, the newsroom’s editor and the company’s senior vice president. “We focused on working-class families and their children, and because of that more infants will grow into adults. And that’s something you can feel really good about.”

Barnes and Managing Editor Rene Sanchez broke the news to the reporters shortly after 2 p.m., when the Pulitzer winners were announced.

The two bolted from their offices clapping and smiling.

Within seconds, dozens of journalists circled Schrade and Olson to hug, shake hands and offer congratulations.

Sack, 59, later paid tribute to the work of his colleagues in a newsroom-wide celebration over cake and champagne.

“I read the paper, I crack a joke and I draw a picture,” he said with a shy grin.

Olson, a former health care reporter at the Omaha World-Herald and St. Paul Pioneer Press who has covered issues involving children and families for the Star Tribune since 2010, was equally humbled.

He had wanted to work at the Star Tribune ever since he delivered the newspaper as a boy growing up in Hopkins.

“There are so many journalists here who I look up to,” said Olson, 39. “Your great work has inspired me to be here.”

Schrade, Olson and Howatt were honored for a nine-month reporting series that began last spring after the paper published a story about a day care facility that was still operating despite a long history of regulatory problems.

“We wondered, ‘How could it take five years to shut this place down?’ ” said Schrade, 43, an investigative reporter at the Star Tribune since 2010.

Over the next several months, the reporters ­collected and examined hundreds of records on suspensions and deaths over the past decade involving the state’s licensed day-care facilities.

Investigating ‘alarming trend’

Star Tribune

Gallery: Steve Sack's Pulitzer winning cartoons

Those records revealed a sharp spike in deaths in recent years. On average, 10 infants were dying each year in licensed day-care facilities. Many of the deaths were linked to violations of basic state guidelines — covering either infant safe-sleep practices or child supervision ratios — and many were preventable.

“That just led to more questions,” Schrade said Monday. “We wanted to know ‘What’s going on in this system? Why are so many kids dying?’ ”

After the series was published, a state child mortality review panel examined 10 years of data and issued a report that found troubling safety breakdowns, including many deaths that involved sleeping infants who had been placed in unsafe sleep positions or environments. The agency proposed a series of safety improvements, including additional training and oversight, and vowed to bring them before the Legislature this session.

State and county regulators also stepped up enforcement, imposing more fines for providers who ignored safe-sleep practices, and increasing communication to the 11,000 in-home providers across the state.

Earlier this month, state officials issued a report saying the “alarming trend” of child-care deaths had been stalled, with just one death in the past eight months.

“I’m proud of the paper and I’m proud of the impact we’ve had in this area,” Schrade said Monday of the series, which was edited by Dave Hage. “There are a lot of parents and people who helped tell the story and were courageous about speaking about the most painful thing a parent can go through.”

The Star Tribune last won a Pulitzer in 1990 for a two-part series that exposed an industry profiting from arson and ­suspicious fires.

JERRY HOLT &#x2022; jerry.holt@startribune.com

Nancy Barnes, editor of the Star Tribune, gave a newsroom toast. “It matters to me that this was for journalism that makes a difference,” she said.